LABORATORY  NOTES 


NON-METALS. 


ARRANGED   FOR   THE  USE 


OF 


STUDENTS 


IN 


GENERAL    CHEMISTRY 


BY 


EDGAR  F.  SMITH  AND  HARRY  F.  KELLER. 

n 


PHILADELPHIA. 

PRESS  OF  EDWARD  STERN  &  Co. 

3r>  33  &  35  'N.  TENTH  ST. 

1890. 


LABORATORY  NOTBS. 

NON-METALS. 
CHAPTER  I. 

APPARATUS,    MANIPULATIONS    AND    OPERATIONS. 

(1)  The  Bunsen  burner  and  the  blowpipe. 

i.  Make  a  borax  bead.  2.  Dissolve  some  manganese  dioxide  in  it. 
j.  Heat  in  the  oxidizing  flame.  4.  In  the  reducing  flame.  5.  Heat  oxide 
of  lead  on  charcoal  in  the  reducing  flame.  6.  In  the  oxidizing  flame. 

(2)  Working  with  glass  tubing  and  rods. 

i.  Cut  various  lengths  of  rods  and  tubing.  2.  Round  the  sharp  edges 
by  softening  and  turning  the  ends  in  the  lamp. 

(3)  Construct  a  wash-bottle  (Fig.  /). 
7.  Soften  a  sound  cork  by  rolling  it  under  your  foot  on 
a  clean  floor.  2.  Bore  two  parallel  holes  through  it  by 
means  of  a  cork-borer.  These  perforations  should  be  cyl- 
indrical and  of  less  diameter  than  the  glass  tubes  they  are  to 
receive.  Use  a  rat-tail  file  in  enlarging  them.  j.  Cut 
suitable  lengths  of  glass  tubing.  ^.  Draw  the  longer  one 
to  a  fine  point  after  softening  in  the  flame.  5.  Bend  the 
tubes  in  an  ordinary  fish-tail  burner,  and  round  the  sharp 
edges.  6.  Fit  the  different  pieces  together. 

(4)  Arrange  some  other  form  of  apparatus  for  practice. 

(5)  The  balance. 

i.  Weigh  an  object  by  placing  it  on  the  left-hand  pan  of  the  balance, 
and  a  weight  judged  about  equal  on  the  right-hand  pan.  Should  the  latter 
be  found  too  heavy,  replace  it  by  the  next  smaller  one  ;  if  too  light,  by  the 
next  heavier  one.  Then  add  systematically  the  smaller  weights,  until  the 
needle  points  to  the  middle  of  the  scale.  The  final  adjustment  is  made 
with  the  rider.  In  adding  or  removing  weights,  the  supports  must  always 
be  raised. 

(6)  Measuring  vessels. 

i.  Measure  off  10  cc.  of  water  (a)  in  a  cylinder,  (b)  in  a  burette,  (c]  in 
a  pipette.  Always  read  the  lower  meniscus.  2.  Measure  off  similarly  50, 
100  and  200  cc.  of  water,  and  determine  their  weight,  j.  Measure  the  vol- 
ume of  5ogrms.  of  oil  of  vitriol,  and  of  65  grms.  of  muriatic  acid.  What 
are  the  specific  gravities  of  these  substances  ?  Note  the  relation  between 
weight  and  volume  in  the  metric  system. 

(7)  Chemical  operations :  Solution,  evaporation,  crystallization,  precip- 
itation, filtration,  washing  and  drying. 

7.  Place  into  a  test  tube  pure  sodium  carbonate,  into  another  cobalt 
chloride,  and  add  distilled  water  to  each.  Stir.  What  occurs  ?  2.  To  cal- 
cium carbonate,  add  water.  Is  there  any  change  ?  Now  add  a  little  hydro- 
chloric acid.  What  action  has  it?  j.  Pour  some  strong  hydrochloric 
acid  upon  powdered  manganese  dioxide  ;  observe  appearance  and 
o lor.  Note,  too,  in  each  case,  whether  heat  has  any  effect.  Distinguish 


between  chemical  and  mechanical  solution.  /.  Heat  the  cobalt  chloride 
and  the  calcium  carbonate  solutions  in  porcelain  dishes  on  an  iron  plate, 
until  the  liquids  are  completely  driven  off  (?).  5.  Dissolve  potassium  chlo- 
rate in  hot  water,  and  allow  to  stand  and  cool  (?).  6.  To  a  portion  of  the 
above  cobalt  chloride  solution,  add  a  solution  of  soda  ;  boil.  7.  Allow  to 
settle  and  filter.  S.  Wash  the  precipitate  until  pure  water  runs  through  the 
filter  (?).  9.  Heat  the  filter  until  perfectly  dry. 

CHAPTER  II. 

GENERAIy    PRINCIPLES. 

(i)  Changes  in  matter. 

i.  Rub  a  glass  rod  with  a  piece  of  cloth,  then  touch  particles  of  paper 
with  it  (?).  2.  Through  an  insulated  spiral  of  stout  copper  wire  pass  a  cur- 
rent from  two  Bunsen  cells.  Place  a  piece  of  wrought-iron — a  nail  will 
answer — inside  the  spiral,  and  bring  iron  filings  in  contact  with  it.  What 
happens  ?  Interrupt  the  current  and  note  the  result ;  repeat,  j.  Heat 
a  platinum  wire  in  the  non-luminous  flame  ;  is  there  any  change  ?  What  is 
the  effect  of  removing  it  ? 

Are  the  original  properties  of  the  substances  in  the  above  experiments 
altered,  after  the  action  of  the  forces  of  electricity,  magnetism  and  heat  has 
been  stopped? 

^r.  Mix  intimately  four  parts,  by  weight,  of  finely  powdered  sulphur 
with  seven  parts  of  very  finely  divided  iron  (filings).  Pass  a  magnet  over  a 
portion  of  the  mixture.  Another  portion  treat  with  carbon  disulphide  in  a 
test  tube.  Then  heat  the  remainder  in  a  tube  over  a  gas  flame.  Note 
carefully  what  occurs  in  each  case.  Powder  the  mass  resulting 
from  the  last  operation  in  a  dry  mortar.  Can  you  extract  from 
it  any  iron  with  a  magnet,  or  dissolve  out  any  sulphur  with  car- 
bon disulphide  ?  What  inference  do  you  draw  from  the  facts 
observed  ?  5.  Moisten  a  bright  piece  of  iron  with  water  and 
expose  it  to  the  action  of  the  air  for  a  few  hours.  6.  Decompose 
water  in  Hofmann's  apparatus  by  an  electric  current.  The 
water  should  be  acidulated  with  sulphuric  acid  to  make  it  a 
conductor  of  electricity.  A  current  from  four  to  six  Bunsen  cells  is 
required.  To  the  gas,  of  which  a  larger  volume  has  collected,  apply  a 
flame,  and  to  the  other  a  glowing  spark.  7.  Heat  oxide  of  mercury  in  a 
tube  of  hard  glass  {Fig.  2).  Apply  the  spark  test.  8.  Rub  some  sulphur 
and  mercury  together  in  a  mortar.  9.  Heat  sugar  in  a  dry  test  tube,  at 
first  gently,  and  then  more  strongly.  Note  color  and  odor.  10.  Mix 
dry  soda  and  tartaric  acid  in  a  mortar.  Is  there  any  action  ?  What  occurs 
when  you  add  water  ? 

(2)  Point  out  in  what  respect  the  changes  involved  in  experiments  /-j 
differ  essentially  from  those  in  4-10.     By  what  general  names  can  you  dis- 
tinguish  the   two  different   kinds?     With   which  does  chemistry  concern 
itself?     Define  chemistry. 

Through  what  agencies  have  the  results  been  obtained  in  experiments 
4-10  ?  Has  any  gain  or  loss  of  matter  occurred  in  any  of  them  ? 

(3)  The  products  resulting  from  6  and  7  cannot  be  further  simplified, 
i.e.,  decomposed  into  dissimilar  substances.     They  are  elements,    What  are 
water  and  red  oxide  of  mercury  ? 


5 


/.  Dissolve  in  a  little  nitric  acid,  the  black  powder  obtained  by  heating 
an  intimate  mixture  of  powdered  sulphur  and  copper  filings. 

<)  3-  Evaporate  the  solution  nearly  to  dryness,  take  up  in  water  and 
filter.  What  remains  on  the  filter?  Place  the  filtrate  in  a 
beaker,  dip  the  platinum  electrodes  of  a  battery  into  it  (Fig.  j}, 
and  allow  the  current  to  act  for  ten  minutes.  What  do  you 
observe  upon  the  platinum  foil,  forming  the  negative  pole? 
What  changes  have  the  copper  and  the  sulphur  undergone  in 
this  experiment  ? 

(Study  pp.  18-27,  in  Richter's  Chemistry.) 

(4)  Metals  and  non-metals.     (See  Richter,  p.  20.) 


CHAPTER  III. 
HYDROGEN. — H. 

(i)  Put  several  pieces  of  granulated  zinc  into  a  test  tube  and   pour 
dilute  sulphuric  acid  upon  them.     What  occurs  ? 

(2)  Arrange  the   apparatus  shown   in   Fig,   4.. 
The  flask  should  contain  about  15  grms.  of  Zn,  and 
dilute  H2SO4  is  poured  through  the  funnel  tube. 
When   all  the   air  in  the  apparatus  has  been   dis- 
placed (ask  for  precautions!)  collect  six  test  tubes 
full  of  the  gas  over  water. 

(3)  What   are  its  properties?      Will   it  burn? 
Support  combustion  ?     Is  it  lighter  than  air  ? 

Connect  the  poles  of  a  Bunsen  battery  (3  cells)  with  a  thin  platinum 


wire.     What  happens  ? 


Now  fill  a  beaker  with  the  gas  you  have  prepared, 
and  with  the  mouth  down  drop  it  over  the  glowing 
.vire  (Fig.  5).  Result? 

(4)  7.  To  learn  what  becomes  of  hydrogen 
when  it  burns  in  air,  arrange  apparatus  as  in  Fig.  6. 
The  gas  is  led  from  the  evolution  flask  At  into  a 
bottle  containing  some  concentrated  H2SO4,  and 
then  passes  through  a  tube  filled  with  pieces  of 
CaCl2.  The  gas  which  escapes  is  free  from  mois- 
ture. Burn  it  under  a  cold  glass  jar.  What  do  you 
obtain  ?  2.  Fill  a  small  flask  with  a  mixture  of  one  vol.  of  H  and  five  vols. 
of  air  ;  cork  ;  invert  the  flask  several  times  to  mix  the  gases  ;  wrap  a  towel 
around  it  and  bring  its  mouth  to  a  flame.  Result  ? 

<$  ^~^r\  (&  Hydrogen  is   not  the  only  pro- 

duct of  the  action  of  H2SO4  upon  Zn. 

Pour  some  of  the  liquid  remaining 
in  the  flask,  in  which  H  was  generated, 
into  a  porcelain  dish.  Evaporate  to 
about  one-third  of  the  original  bulk  ; 
allow  to  stand  for  some  hours.  You 
will  now  discover  that  the  solution  is 
full  of  colorless  crystals.  Thesfe  are  zinc  sulphate  or  white  vitriol— a  salt, 
ZnSO4-f  7H2O.  Write  the  equation  of  the  reaction. 


(6)  Determine  the  weight  of  H  generated  by  a  given  weight  of  Zn. 

A  piece  of  Zn  (not  more  than  '02  grm. )  is  accurately 
weighed,  and  placed  under  a  funnel  in  a  beaker  (Fig.  7). 
The  beaker  is  then  nearly  filled  with  water,  so  that  the  entire 
funnel  is  under  the  surface.  A  test  tube  containing  dilute 
H2SO4  is  lowered  over  the  stem  of  the  funnel.  Hydrogen 
appears  and  collects  in  the  tube.  When  all  the  Zn  has  dis- 
appeared, *  transfer  the  tube  containing  the  H  to  a  larger  vessel, 
holding  water.  Measure  the  volume  of  the  gas  by  marking 
the  tube  where  the  inner  and  outer  levels  of  water  are  even, 
and  then  weighing  or  measuring  the  quantity  of  water  that  it  will  hold  to 
that  mark.  Note  the  temperature  of  the  water,  and  the  height  of  the 
barometer. 

The  weight  of  the  H  is  found  by  multiplying  the  vol.  by  the  wt.  of 
i  cc.,  i.  <?.,  '0000896  gr.  Before  this  can  be  done,  however,  it  is  necessary  to 
reduce  the  volume  of  the  gas  to  o°  C.  and  760  mm. ,  as  the  above  value  has 
been  determined  under  these  conditions.  If  v  =  volume  observed,  t  = 
temperature,  and  p  =  pressure,  then 


say  — 


'  fs 


(I   +    «t)  +  760 

2)  and  W  =  v0  X  '0000896  .  «  —  '003665. 

To  calculate  the  quantity  of  Zn,  necessary  to  generate  a  unit  of  H,  we 

Wt  of  H  :  Wt  of  Zn  :  :  i  :  x. 
x  here  stands  for  the  equivalent  weight  of  Zn. 

The  equivalent  weights  of  some  other  metals,  such  as  Fe,  Cd,  Mg,  can 
be  determined  in  the  same  manner. 

.  Problems. — /.  How  much  H  can  be  obtained  from  Zn 

and  299  grms.  of  H2SO4?  2.  How  much  Znand  H2SO4  are 
necessary  to  furnish  100  grms.  of  H  ?  j.  Suppose  you  have 
found  that  '15  grms.  of  Mg  yield  15*2  cc.  of  H  at  20°  C.  and 
750  mm.,  what  is  the  equivalent  weight  of  that  metal  ? 

(7)  Decompose  water  by  electrolysis   and  test  the  pro- 
ducts. 

(8)  Take  a  small  piece  of  sodium,  wrap  it  in  paper  and  place  it,  with 
forceps,  under  the  mouth  of  a  test  tube  filled  with  water,  and  inverted  in 

water  (Fig.  8}  contained  in  a  dish. 
Repeat  this  until  the  test  tube  is  filled 
with  the  gas.  Test  it  for  H. 

What  becomes  of  the  metal  ?     Write 
the  reaction. 

(9)  Construct  the  apparatus  shown 
in  Fig.  9. 

Water  is  heated  to  boiling  in  the 
flask  A,  and  the   steam  led  over  iron 
filings  or  wire,  heated  to  redness  in  a  tube  of  hard  glass.     Care  must  be 

1  This  may  be  hastened  by  b  inging  a  spiral  of  platinum  wire  in  contact  with  the  Zn. 
2)  Tension  of  aqueous  vapor  is  here  neglected. 


taken  to  prevent  steatn  from  condensing  in  any  part  of  the  tube.     Collect 
the  escaping  gas  over  water.     Test  it  for  H. 
Is  the  iron  changed  ?     Equation  ? 

,  t       /o  (10)  Into  a  weighed  tube  of  hard  glass  put 

a  weighed  quantity  of  CuO  ;  connect  the  tube 
with  a  CaCl2  tube  of  known  weight  (Fig.  id}. 
Pass  a  current  of  dry  H  over  the  CuO  and  heat. 
After  the  change  is  complete,  cool  and  deter- 
mine the  loss  in  weight  of  tube  -\-  CuO,  and 
the  gain  in  the  CaCl2  tube.  Explain  the  reaction. 

Problems. — /.  How  many  cc.  of  H  can  be  obtained  from  2  grms.  of 
Na?  2.  How  many  grms.  of  H2O  can  be  decomposed  by  5  grms.  of  Fe  ; 
by  how  much  is  the  weight  of  the  latter  increased  ?  j.  10  grms.  of  CuO  will 
yield  how  much  Cu  upon  heating  in  H  ? 

Give  a  brief  summary  of  what  you  have  learned  about  H. 
(Study  Richter,  pp.  39-47.) 

CHAPTER  IV. 

FIRST  NATURAL,  GROUP  OF  ELEMENTS—  CHLORINE,  BROMINE,  IODINE, 

FLUORINE. 

CHLORINE. — Cl. 

i)  Into  a  test  tube  put  MnO2  and  HC1.     Note  what  happens  both 
before  and  after  heating. 

(2)  Use  apparatus  (shown  in  Fig.  //)  for  preparing 
larger  quantities  of  Cl.     The  MnO2  should  be  in  the 
form  of  small  lumps  (not  powder).     Heat  the  mixture 
gently,  pass  the  Cl  through  water  and  collect  it  either 
by  downward  displacement  or  over  warm  water. 

Write  the  reaction.     How  many  atoms  of  Cl  are 
liberated  ?    How  many  molecules  ? 

(3)  /.  What  is  the  normal  condition  of  this  element  ? 
2.  Is  it  lighter  than  air  ?    j.  Is  it  inflammable?    ^.  Does 
it  support  combustion  ? 

To  obtain  answers  to  these  questions,  fill  5  test  tubes  with  dry  Cl,  and 
proceed  as  under  H. 

(4)  Again  fill  5  bottles  with  the  dry  gas.    Cover  them  with  glass  plates. 
Into  /  throw  a  little  pulverized  antimony. 

Into  2  carefully  introduce  a  piece  of  phosphorus. 

Into  3  insert  tissue  paper  moistened  with  oil  of  turpentine. 

Into  4.  introduce  colored  flowers. 

Into  5  pour  a  little  litmus  solution. 

What  are  the  results  ? 

(5)  Fill  a  small-sized  flask  one-half  with  chlorine,  the  other  half  with 
hydrogen.     Wrap  a  towel  about  the  flask  and  apply  a  flame  to  its  open 
mouth  (?).     Care. 

(6)  Invert  a  bottle  filled  with  Cl  over  water  saturated  with  the  same 
gas.     What  follows  in  the  course  of  a  few  hours'  exposure  to  sunlight? 


8 

Can  you  account  for  results  in  experiments  /,  5  and  6  ?    Why  should  the 
gas  be  collected  over  warm  water  ? 

(7)  7.  Saturate  water  with  Cl ;  cool  below  o°  C.     What  do  you  obtain  ? 
2.  Place  some  of  the  product  in  the  closed  limb  of  a 
bent  tube  (Fig.  12] ;  seal  the  open  end.     Now  warm  the 
end  containing  the  substance,  in  a  water  bath,  to  about 
'/  30°,  while  you  cool  the  other  end  in  snow.     What  is  the 

liquid  which  collects  in  a  ?    What  occurs  when  a  is  warmed  and  b  is  placed 
in  snow  ? 

(8)  Determine  the  weight  of  a  litre  of  chlorine.    Arrange  apparatus  shown 
in  Fig.  13. 

In  the  evolution  flask  place  a  mixture  of  equal 
weights  of  salt  and  manganese  dioxide.  Add  sul- 
phuric acid,  previously  diluted  with  its  own  volume  of 
water  (pour  the  acid  into  the  water  !).  Heat  gently, 
and  conduct  the  Cl  into  the  perfectly  dry  flask  c. 
When  this  is  filled,  which  you  ascertain  by  the  color 
of  the  gas  in  the  neck,  slowly  withdraw  the  tube  and 
cork  the  flask  at  once.  Weigh  the  flask,  and  note  the 
atmospheric  temperature  and  pressure.  Determine,  also,  the  weights  of  the 
flask  filled  with  air  and  with  water. 
Calculation : 

Capacity  of  flask,       a 

Temperature, t 

Pressure, p 

Flask  filled  with  air, ...» w 

Cl,      w' 

Wt.  of  a  litre  of  air, i*293grm. 

Cl, ••;.• x 

The  weight  of  the  air  filling  the  flask,     ?  X  P  +  '001293      The  differ_ 

(i  -f  -00367^760 

ence  between  this  and  w  is  the  weight  of  the  vacuous  flask.     Subtract  this 
from  w'.     The  remainder  is  the  weight  of  the  Cl,  (W).     Reduce  the  vol.  of 


the  Cl  to  o°  C.  and  760  mm.  (see  under  H) ;  it  is  v0  =  —   — _ ,  and 

WXiooo  (i  X -003671)760 

the  weight  of  i  litre,  x  =     w  x  I00°  . 

v0 

How  much  heavier  is  i  litre  of  Cl  than  an  equal  vol.  of  H  ? 

Write  the  reaction  involved  in  the  above  method  for  preparing  Cl. 

Problems. — /.  How  many  litres  of  Cl  can  be  obtained  from  i  kilo  of 
MnO2  and  HC1  ?  2.  What  weight  of  salt  is  required  to  prepare  100  litres  of 
Cl  ?  Write  put  your  deductions  from  the  above  experiments  on  Cl. 

(Read  Richter,  pp.  49-52.) 

HYDROGEN  CHLORIDE. — HC1. 

(i)  Repeat  the  explosion  of  equal  vols.  of  Cl  and  H.  Quickly  cover  the 
mouth  of  the  flask,  and  immerse  it  under  water.  Does  the  latter  rise  ?  Put 
a  drop  of  the  liquid  on  the  tongue  and  note  the  taste.  Add  some  blue  litmus 
solution.  Is  there  any  change  ? 


(2)  The  product  of  the  union  of  H  and  Cl  is  a  colorless  gas.    It  is  called 
hydrogen  chloride.     It  is  usually  prepared  by  the  action  of  sulphuric  acid 
upon  salt,  thus  : 

2NaCl  +  H2SO4  =  2HC1  -f  Na2SO4. 
or,  better,  NaCl  -f  H2SO4  =    HC1  -j    NaHSO4. 

The  apparatus  is  the  same  as  that  used  for  making  Cl  (Fig.  /j). 

(3)  Determine  the  properties  of  HCl  as  under  H  and  Cl. 

What  new  property  appears  here  ?  Fill  a  long  dry  glass  tube  with  the 
gas,  and  quickly  bring  it  into  a  basin  containing  water  colored  blue  with 
litmus.  What  happens  ?  What  does  HCl  gas  yield  on  dissolving  in  water  ? 

(4)  In  the  preparation  of  H  by  the  action  of  Na  upon  water,  it  was 
observed  that  the  liquid  became  soapy  to  the  touch,  and   acquired  the 
property  of  turning  red  litmus  blue.     Prepare  such  a  solution.     To  it  add  a 
few  drops  of  litmus,  and  then  an  HCl  solution  (gradually)  from  a  burette, 
until  the  blue  color  just  begins  to  turn.     Evaporate  the  resulting  liquid  to 
crystallization.    Dissolve  and  recrystallize  the  product.    It  appears  in  cubes, 
and  has  the  taste  of  common  salt.    It  does  not  affect  either  red  or  blue  litmus. 
We  say  it  is  neutral  in  reaction.     The  substance  is  chloride  of  sodium  or 
common  salt.     What  is  a  salt  ?     An  acid  ?     A  base  ?     How  can  you  obtain 
HCl  and  Cl  from  NaCl  ? 

(5)  Burn  H  in  an  atmosphere  of  Cl,  and  Cl  in  hydrogen. 

(6)  To  determine  the  iveight  of  a  litre  of  HCl,  proceed  exactly  as  under 
chlorine. 

(7)  Determine  the  composition  of  HCl  by  volume. 

1.  Decompose  concentrated  HCl  by  means  of  the  electric  current  in 
Hofmann's  apparatus.     Carbon  electrodes  should  be  used  here.     Test  the 
two  gases  ;  the  H  with  a  taper,  and  the  Cl  by  bleaching  a  moist  piece  of 
calico.     After  the  action  of  the  current  has  continued  for  some  time,  close 
the  stopcocks  and  note  the  relative  volumes  of  the  gases. 

2.  Fill  a  perfectly  dry  and  graduated  tube  with  HCl.     Close  the  open 
end  with  the  thumb,  and  opening  the  tube  for  a  moment,  quickly  pour  in 
about  10  cc.  of  sodium  amalgam.     Close  the  tube  at  once  with  the  thumb, 
slightly  moist,  and  shake  well.     Invert  the  tube  in  a  large  beaker  of  water, 
and  remove  the  thumb.     The  amalgam  will  drop  into  the  water,  and  the 
latter  will  rush  up  into  the  tube,  filling  it  nearly  half  full.     Immerse  the 
tube  so  that  the  water  in  it  and  that  in  the  beaker  are  on  the  same  level. 
This  is  done  to  measure  the  hydrogen  under  atmospheric  pressure.     Read 
the  residual  volume  of  the  gas  and  measure  the  volume  of  the  mercury. 

Calculation : 

Capacity  of  tube, a 

Vol.  of  mercury, b 

Vol.  of  H, .  c 

c  =  a  —  b 
2 

(8)  Add  a  solution  of  HCl  to  solutions  of  silver  nitrate  ;  of  mercurous 
nitrate  ;  and  of  lead  acetate.     What  do  you  observe  in  each  case  ?     Boil  the 
precipitate  formed  in  the  lead  solution  with  water.     Cool,  and  note  result. 


10 

BROMINE. — Br. 

(1)  Allow  a  drop  of  bromine  to  fall  upon  a  heated  watch  glass  ;  cover 
it   quickly  with  a  beaker.     What   is   the   color  of  the   vapor?     Dissolve 
bromine  in  alcohol,  in  ether,  in  carbon  disulphide,  and  in  chloroform.    Note 
the  relative  solubilities,  and  the  color  of  each  solution. 

(2)  7.  Pass  Cl  through  an  aqueous  solution  of  K  Br ;  what  happens  ? 
2.  To  one  portion  of  the  product  add  a  few  drops  of  CS2,  and  agitate  the 

mixture  ;  what  is  the  result  ?    j.  To  another  por- 
J~ij     f<t  tion  of  the  solution,  containing  free  Br,  add  a  few 

drops  of  a  starch  solution.     (This  is  made  by  boil- 
ing starch  with  water  and  filtering).     Result  ? 

(4)  Devise  a  method  for  preparing  bromine 
from  K  Br. 

(5)  Prepare  hydrobromic  acid. — In  a  small 
flask  cover  i  part  of  amorphous  phosphorus  with 
2  pts.  of  H2O,  and  from  a  funnel,  provided  with  a 

stopcock,  gradually  allow  10  pts.  of  Br  to  run  in.  The  gas  is  purified  by  con- 
ducting it  through  a  U-tube,  containing  moistened  pieces  of  phosphorus  and 
glass.  (Fig.  14.} 

(6)  Prepare  AgBr,  HgBr  and  PbBr2  ;  do  they  differ  much  from  the 
chlorides  ? 

IODINE. — I. 

(i)  7.  Place  an  iodine  crystal  upon  a  warm  plate,  and  note  color  of 
vapor.  2.  Test  the  solubility  of  iodine  in  various  liquids  ;  what  are  the 
colors  of  the  resulting  solutions  ? 

(2)7.  Pass  Cl  through  a  solution  of  KI.  Test  the  resulting  liquid  with 
ether,  carbon  disulphide  and  starch  solution  (as  with  Br).  2.  Repeat  this 
experiment,  substituting  Br-water  for  the  Cl.  Avoid  excess  of  Cl  as  well  as 
Br  (?). 

What  conclusion  do  you  draw  relative  to  the  affinity  of  the  halogens 
for  potassium  from  these  experiments  ? 

(3)  Pass  hydrogen  sulphide  gas  (H2S)  into  50  cc.  of  water,  and  add 
powdered  iodine  till  the  brown  color  no  longer  disappears.     Warm,  filter  (?) 
and  distil  the  filtrate.     The  product  is  what  ? 

How  is  gaseous  HI  prepared  ? 

(4)  Precipitate  solutions  of  silver  nitrate  (AgNO3),  mercurous  nitrate 
(HgNO3),  lead  nitrate  (Pb(NO3)2),and  mercuric  chloride  (HgCl2)  with  KI. 

FLUORINE. — Fl. 

(1)  In  a  lead  dish  (or  platinum  crucible)  place  i  gram  of  pulverized 
fluor  spar  (CaFl2).     Add  cone.  H2SO4  ;  cover  the  dish  or  crucible  with  a 
watch  glass  coated  with  paraffin,  through  which  some  characters  have  been 

'drawn  with  a  fine  point.     Heat  gently  for  a  few  minutes. 
What  do  you  observe  on  removing  the  paraffin  ? 

(2)  Can  you  liberate  Fl  from  a  fluoride  ? 

Problems. — i.  How  much  NaBr,  H2SO4  and  MnO2  are  necessary  to 
produce  i  cu.  metre  of  Br?  2.  What  per  cent,  of  HI  does  a  liquid  contain, 
which  represents  a  solution  of  50  litres  of  the  gas  in  i  litre  of  H2O  ?  3.  10 
grms.  of  CaFl  2  will  give  what  weight  of  HF1  ? 


II 


CHAPTER  V. 

SECOND   NATURAL  GROUP   OF   ELEMENTS — OXYGEN,  SULPHUR, 

(Selenium,  Tellurium}. 

OXYGEN.- — O. 

(i)  Preparation.— i.     Weigh  the  hard  glass  tube  a  (Fig.  75),  and  intro- 
duce a  xveighed  quantity  (about  '5  grm.)  of  red  oxide  of  mercury.     Ignite 

strongly  ;  collect  the  liberated  gas,  and  measure 
it.  Weigh  the  tube  with  the  residue.  What 
are  the  products  of  the  ignition  ? 

Prepare  more  of  the  gas,  as  follows  :  Mix 
equal  parts  of  KC1O3  and  pulverized  MnO2; 
heat  in  a  tube  of  hard  glass  or  small  retort. 
Collect  the  gas  in  bottles  over  water.  (Fig.  16. ) 
(2)  Into  No.  .1  lower  a  piece  of  ignited 
sulphur  on  a  copper  spoon.  Note  result.  Add 
water  after  the  combustion. 

Into    No.    2   introduce   a  small    piece    of 
burning  phosphorus  (care  !).     Proceed  as  in  No.  i. 

Into  No.  3  introduce  ignited  charcoal.     Treat  as  before.     Add  now  a 
few  drops  of  blue  litmus  to  the  contents  of  each  vessel.     Any  change  ? 

Into  bottle  No.  4  introduce  a  fine  watch  spring,  previously  heated  at 
one  end  and  dipped  into  powdered  S.     Result  ? 

Is  oxygen  heavier  or  lighter  than  air  ?     Has  it  color,  taste,  or  odor  ? 
Will  it  burn  ?     Does  it  support  combustion  ? 

What  other  methods  can  be  used  for  preparing  O  ? 
(3;  Determine  the  iveight  of  a  litre  of  O. 

Arrange  apparatus  shown  in  Fig.  77  /  a  is  a 
tube  of  hard  glass,  whose  weight  is  known  ;  it 
contains  a  weighed  amount  of  KC1O3  (about  3 
grm.).  The  bottle  A  is  filled  with  water,  b  is  a 
clip  and  d  a  beaker.  Open  the  clip,  heat  a  to 
bright  redness,  and  receive  the  water  displaced 
by  the  O  in  d.  When  no  more  gas  is  evolved, 
cool ;  allowing  the  rubber  tube  to  dip  under  the 
water  of  the  jar.  Some  of  the  water  will  be 
drawn  back  into  the  bottle  (?).  Measure  the  volume  of  the  water  in  d.  Note 
the  temperature  of  the  air,  and  the  height  of  the  barometer.  Weigh  a, 
containing  residue  (KC1). 
Calculation  : 

Weight  of  the  tube, a 

Weight  of  KC1O3  and  tube, b 

Weight  of  KC1O3, b  —  a 

Volume  of  H2O  collected, v 

Barometric  pressure, p 

Temperature, t 

Aqueous  tension  at  t, p7 

Weight  of  KC1  and  tube, c 

v  X  (p  —  V}  ,  (b  — c)  X  looo 

Vo  ~  (i  +  -00367  t)  X  76o 


and 


12 


Dissolve  the  residual  KC1  in  water,  and  to  its  solution  add  nitrate  of 
silver  (?).  How  does  KC1O3  behave  under  like  conditions  ? 

(4)  Give  a  summary  of  your  work  upon  O. 

Problems. — /.  How  much  O,  by  wt.  and  vol.,  can  be  obtained  from  54 
grms.  of  HgO?  2.  Heat  will  expel  what  vol.  of  O  from  2-45  grms.  of 
KC1O8  ?  j.  How  much  HgO  is  necessary  to  yield  i  cu.  d.  m.  of  O  ?  4.  How 
many  times  is  O  heavier  than  H  ? 

OZONE.— O3. 

(1)  Partly  fill  a  straight  eudiometer  tube  with  oxygen,  over  a  dilute  solu- 
tion of  KI  mixed  with  starch.    Pass  the  spark  for  some  time.  What  occurs  ? 

(2)  Pour  water  on  clean   pieces   of  phosphorus   to   half  cover  them  ; 
invert  a  large,  clean  jar  over  this  and  allow  to  stand  for  several  hours. 
Test  the  air  under  the  jar  for  ozone. 

(Read  Richter,  p.  85-89.) 

COMPOUNDS  OF  OXYGEN  AND  HYDROGEN. 

WATER.— H2O. 

(i)  Arrange  the  distillation  apparatus  (Fig.  18)  and  prepare  about  100  cc. 
of  distilled  water.  Note  its  taste  and  odor.  Test  it  for  chlorides  with  AgNO  3  ; 

for  nitrates  and  organic  matter.  Does 
it  leave  a  residue  upon  evaporation  ? 
What -action  has  it  on  litmus  ? 

Apply  all  these  tests  to  a  natural 
water  (except  rain). 

(2)  /.  Heat  a  little  vegetable  mat- 
ter in  a  dry  test  tube.  2.  Heat  fresh 
meat  in  the  same  manner,  j.  Care- 
fully heat  crystals  of  zinc  or  copper 
sulphate  in  a  test  tube.  What  hap- 
pens in  these  experiments  ?  ^.  Expose  clear  crystals  of  sodium  phosphate, 
on  a  watch  crystal,  to  the  air.  5.  Do  the  same  with  pieces  of  calcium 
chloride.  Results  ? 

(3)  Determine  the  quantitative  composition  of  water. 

1.  The  composition  of  water  by  weight  follows  from  the  experiment  of 
reducing  oxide  of  copper,  described  under  H. 

2.  The  relative  volumes,  with  which  O  and  H  unite  to  form  water,  are 
determined  either  by  analysis  or  synthesis.      The  former  has  been  per- 
formed in  electrolyzing  water. 

3.  Fill  a  eudiometer  (Fig.  so)  with  water.     Through  a  rubber  tube  admit 
about  50  cc.  of  O  and  then  a  like  volume  of  H.      (If  the  eudiometer  is 

not  graduated,  mark  these  with  rubber  bands).  Close 
the  open  end  with  your  thumb,  leaving  some  air  to  serve 
as  a  cushion  beneath  it,  and  pass  the  spark.  Remove 
the  thumb,  and  pour  in  enough  water  to  make  the  levels 
equal  in  both  limbs.  What  is  the  amount  of  the  con- 
traction ?  What  is  the  residual  gas  ?  Test  it. 

(4)  Determine  the  weight  of  a  litre  of  steam. — Con- 
struct apparatus  shown  in  Fig.  20.     The  flask  a  is  closed 
^^Zr          by  a  cork  perforated  with  two  holes  ;  one  is  about  i  cm. 
wide,  the  other  about  4  mm.  wide.     A  short  straight  piece  of  glass  tubing 


Ay  /y. 


passes  through  the  wider  hole,  while  the  other  receives  the  bent  tube  b.     C 

is  an  iron  pot  with  a  perforated  lid, 
through  which  passes  the  neck  of  the 
flask.  The  bottom  of  the  iron  vessel  is 
covered  with  sand.  A  small  glass  tube 
is  weighed  and  rilled  with  water  (not 
more  than  '02  grm.).  Heat  the  iron  pot 
with  a  Bunsen  burner  until  the  tempera- 
ture is  constant  (?).  Now  drop  the  tube 
containing  the  water  through  the  wide 
tube  of  the  flask  (the  bottom  of  which 
should  be  protected  with  a  layer*  of 
asbestos)  and  quickly  cork  the  wide  tube.  When  the  flow  of  water  ceases, 
make  the  levels  of  the  water  in  the  beaker  and  the  bottle  coincide.  Uncork 
the  wide  tube  and  remove  the  flame. 

Measure  the  water  and  note  the  temperature  and  pressure  of  the  air. 
The  calculation  is  analogous  to  that  used  under  O. 
(5)  Perform  experiment  2,  p.  100  in  Richter. 

How  many  volumes  of  steam  result  from  the  combination  of  2  vols.  of 
H  and  i  vol.  of  O  ? 

What  is  the  molecular  formula  of  water  ? 


HYDROGEN  PEROXIDE.— H2O2. 

(1)  Add  moist  hydrated  barium  peroxide  to  cold  dilute  H2SO4.     Filter. 
What  does  the  filtrate  contain  ? 

(2)  /.  Add  a  solution  of  KI,  containing  starch,  to  this  liquid.     Ferrous 
sulphate  may  also    be    added  to   a  portion   of  it.     2.  Add    a   solution   of 
potassium  permanganate  to  another  portion  (?). 


COMPOUNDS  OF  OXYGEN  AND  CHLORINE. 

(1)  Make  a  dilute   solution  of  caustic   potash,  and   conduct  chlorine 
into  it  until  the  latter  is  no  longer  absorbed.      Treat  one  portion  of  the 
product  with  HC1,  and  another  with  H2SO4.     What  results  ? 

(2)  Mix  20  grms.  of  quicklime  with  50  cc.  of  H2O.     After  the  slaking 
is  finished,  conduct  Cl  into  the  mixture  until  it  is  no  longer  absorbed. 

Add  HC1  to  one  portion  and  H2SO4  to  a  second  portion. 
What  is  set  free  ?     Does  it  bleach  ? 

(3)  Pass  Cl  into  a  warm  concentrated  solution  of  KOH  till  it  ceases 
to  be  absorbed.     What  separates  upon  cooling  ?     Recrystallize  the  product 
from  H2O.     Will  it  give  off  O  upon  heating?    Try  the  action  of  HC1  upon 
a  crystal.     Allow  a  drop  of  cone.  H2SO4  to  fall  upon  a  small  crystal  and 
warm  gently  (?).     Care  ! 

Observe  carefully  the  behavior  of  KC1O3  upon  heating  (?). 


SULPHUR. — S. 

(1)  Wherein  does  sulphur  differ  from  the  elements  previously  studied  ? 

(2)  Place  a  few  grams  of  powdered  S  in  a  dry  test  tube,  and  heat  gradu- 
ally.    Observe  and  describe  the  changes  which  occur. 


14 

(3)  Dissolve  some  S  in  CS2  and  allow  to  stand  till  the  liquid  has  evapo- 
rated.    What  remains  ? 

(4)  Determine  the  sp.  gr.  of  S  (Fig.  21}.     A  small  flask  with  narrow 
neck  is  filled  with  water  (boiled  shortly  before)  to  a  mark  upon  the  neck. 

Weigh  the  flask,  then  place  an  additional  10  grm.  weight  upon  the 
right-hand  pan  of  the  balance  and  small  pieces  of  S  upon  the  left- 
hand  pan,  until  the  pointer  is  again  in  the  middle.  Now  introduce 
the  S  into  the  flask.  Carefully  remove  the  water  above  the  mark 
and  re-weigh  the  flask  with  its  contents.  The  loss  in  weight  will 
represent  the  weight  of  a  volume  of  water,  equal  to  that  of  10 
grms.  of  S.  The  latter  divided  by  the  former  is  the  quantity 
sofight. 

(5)  Prepare  the  monoclinic  modification  of  S  by  melting  about  10  grms. 
of  the  ordinary  variety  in  a  Hessian  crucible.     Cool  ;  and  as  soon  as  a  solid 
crust  has  formed  upon  the  surface,  pierce  it  and  allow  the  still  liquid  portion 
of  the  contents  to  run  out.     Note  the  shape  of  the  crystals  upon  the  sides 
of  the  crucible. 

(6)  To  obtain  the  plastic  variety,  heat  10  grams  of  S  in   a  test  tube 
above  230°  C.,  and  poiir  the  mass  into  cold  water. 

Test  the  solubility  of  the  product  in  CS2.     Preserve  a  portion  of  it  for 
several  days.     Does  it  change  ? 

(7)  To   a   strong  solution   of  yellow  potassium    sulphide,    add    HC1. 
What  are  the  properties  of  the  separated  sulphur  ? 

Give  a  brief  outline  of  the  element  sulphur  ;  contrast  it  with  the  pre- 
viously studied  elements. 

SULPHUR  AND  HYDROGEN. 

(8)  Over  some  dry  silver  sulphide,  contained  in  a  tube  of  hard  glass, 
conduct  a  current  of  pure  H.     Apply  heat.     What  remains  in  the  tube  ? 
Note  the  odor  of  the  escaping  gas.  as  well  as  its  action  upon  a  piece  of 
paper  moistened  with  a  solution  of  acetate  of  lead. 

(9)  Hydrogen  sulphide  is  formed  only  with  difficulty  from  its  elements, 
but  is  readily  obtained  by  the  action  of  acids  upon  sulphides,  thus  : 

FeS  +  2H2SO4  —  FeSO4  +  H2S  orSb2S3  -[-•  6HC1  ===  2SbCl3  +  3H2S. 

The  apparatus  to  be  used  is  the  same  as  that  employed  in  preparing 
hydrogen. 

(10)  What  are  the  properties  of  H2S?     Is  it  soluble  in  water?     Does  it 
burn  ?     What  are  its  products  of  combustion  ?     Hold  a  porcelain  plate  in 
the  flame  ;  what  results  ?     Pass  the  gas  into  solutions  of  chromic  acid,  per- 
manganic acid,  and  ferric  chloride.     What  changes  are  observed  ?     How  do 
these  last-named  reactions  show  its  reducing  power  ?     What  happens  to  the 
aqueous  solution  of  the  gas  when  exposed  to  the  air  ?     What  action  has 
the  aqueous  solution  upon  litmus  ?     To  what  class  of  compounds  does  it, 
therefore,  belong  ? 

(u)  Pass  H2S  through  solutions  of  the  following  salts,  viz:   CuSO4, 
SbCl,,  Pb  (NO,) 2,  AsCl3,  and  Zn  (C2H3O2)2.     Note  results  carefully. 
Can  sulphides  be  prepared  in  another  manner  ?     (See  Chap.  II,  $i«) 


15 

(12)  Determine  the  composition  of  hydrogen  sulphide, 

Into  a  bent  tube  of  hard  glass,  filled  with  mercury, 
(Fig.  22)  y  introduce  dry  hydrogen  sulphide.  Place  a 
piece  of  tin  in  the  bent  portion,  and  heat  it.  Is  the  vol- 
ume of  the  gas  changed  after  the  experiment,  and  what 
becomes  of  the  piece  of  tin  ?  Test  the  gas  remaining  in 
the  tube.  Do  your  results  enable  you  to  deduce  the 
molecular  formula  of  H2S?  (See  Richter,  3d  ed.,  p. 

in.)     Trace   the   similarity  between  H2S  and  H2O.    Write  a  summary  of 

your  experiments  on  H2S. 

AND  CHLORINE. 


(13)  Sulphur  Monochloride.  —  Prepare  this   compound  by   conducting 
dry  chlorine  over  molten  sulphur.     The  product  which  distils   over  is  col- 
lected in  a  dry  test  tube,  kept  cold  by  immersion  in  ice  water.     Re-distil 
the  product.     Note  its  color  and  odor.     Expose  some  of  it  to  the  air  on  a 
watch  glass.     Add  water  to  another  portion  contained  in  a  test  tube.     Note 
carefully  what  happens.     Write  the  reaction. 

SULPHUR  AND  OXYGEN. 

(14)  Burn  sulphur  in  the  air.     Result?     Burn  FeS  in  the  air.     What 
are  the  properties  of  the  resulting  compound.     It  is  sulphur  dioxide  —  SO2. 

(15)  Fit  a  small  flask  as  indicated  in  Fig.  23.  Place 
copper  turnings  in  it,  then  addH2SO4  (strong)  through  the 
funnel  tube.  Warm.  Is  the  product  the  same  as  that 
obtained  in  14?  Is  it  soluble  in  water?  Has  the  aqueous 
solution  the  same  properties  as  the  gas  ?  2.  Pass  some  of 
the  gas  into  acidulated  solutions  of  potassium  dichromate 
and  potassium  permanganate.  Repeat  these  experiments 
with  the  aqueous  solution  instead  of  the  gas.  What  hap- 
pens in  each  case  ?  j.  Test  the  aqueous  solution  of  SO2  with 
litmus.  What  is  this  solution  commonly  called?  4.  Fill  a 
dry  jar  with  SO2  gas;  introduce  colored  flowers.  Note  the  result. 

(16)  What  is  the  formula  of  sulphurous  acid?    How  many  series  of 
salts  can  it  form  ?     How  would  you  designate  the  different  sodium  salts  ? 
AddHClto  a  solution  of  Na2  SO  3.     What  follows?     Evaporate  the  solu- 
tion to  dryness  and  examine  the  residue.     What  is  it  ?     Write  the  reaction. 

SULPHUR  TRIOXIDE  —  SO3  —  and  SULPHURIC  ACID—  H2SO4.  (Read  Rich- 
ter, p.  189.) 

(17)  /.  Prepare   sulphuric  acid  as  described  in  Richter,  p.  191.    Study 
the  product  carefully.     2.  Dilute  a  portion  of  it  with  water  ;  what  happens? 
j.  Test  a  portion  of  this  diluted  solution  with  litmus  (?).     4.  Another  por- 
tion neutralize  with  NaOH  and  evaporate.    What  is  the  residue  ?     Does   it 
contain  any  S  ?  Prove  this.    5.  Add  BaCl2  to  a  third  portion  of  the  solution. 
What  is  the  precipitate  ?     Is  it  soluble  in  water  or  in  acids  ?     6.  What  is  the 
action  of  strong  H2SO4  upon  wood  or  paper?      Explain  the  cause  of  this 
action. 

(18)  How   many  series   of    salts  can  sulphuric  acid    form?       Prepare 
(NH4)2  SO4,  Na2SO4,  NaHSO4  and  CuSO4.      (Read  Richter,  pp.  189-200.) 


i6 


CHAPTER  VI. 

NITROGEN    GROUP— NITROGEN,    PHOSPHORUS,    ARSENIC,    ANTIMONY 

(and  Bismuth}. 
NITROGEN.— N. 

(i)  Preparation. — /.  In  a  dish   swimming   on  water  place  a  piece  of 
phosphorus  and  ignite  it  ;  invert  a  beaker  glass  over  it  (Fig.  24}.     What 
becomes  of  the  P  ?     When  the  latter  has  ceased 
burning,  restore  the  level  of  the  water,  and  note 
the  decrease  in  the  volume  of  the  air.     Test  the 
residual  gas  with  a  burning  taper.     2.  Heat  gently 
in  a  small  flask  or  retort  a  mixture  of  i  part  KNO2, 
i  pt.  NH4C1,  i  pt.  K2Cr2O7,  and  3  pts.  of  H2O  ;  col- 
lect the  gas  over  water.  Fill  five  bottles  with  this  gas. 
(2)  Has  it  color,  taste,  odor  ?     Does  it  burn  or 
support  combustion  ?  Introduce  a  small  animal,  e.g. , 
a  mouse,  into  one  of  the  bottles  ;  what  is  the  result  ? 
Is  the  gas  heavier  than  air  ?     Does  it  unite  readily  with  other  elements  ? 

(3)  Determine  the  weight  of  a  litre  of  nitrogen. — A  round-bottomed 
flask  is  fitted  as  shown  in  Fig.  25.     Pour  about  30  cc.  of  water  into  it,  and 

insert  the  cork  to  the  mark.  Boil  the  water, 
while  the  clip  is  open,  until  all  the  air  has  been 
expelled  from  the  flask.  This  requires  the  steam 
to  blow  out  for  about  five  minutes.  Now  close  the 
tube  with  the  clip,  and  remove  the  flame.  Cool 
and  weigh  the  flask.  Read  the  temperature  and 
barometric  pressure  in  the  balance-room. 

Connect  the  flask  with  the  tube  b  of  the  aspira- 
tor, containing  N  and  arranged  as  in  Fig.  26.  The 
rubber  tube  a  is  made  to  dip  under  water,  and  the 
clip  is  gradually  opened,  allowing  N  to  enter  the  flask.  Now  raise  the 
vessel  containing  the  water  into  which  the  rubber  tube  dips,  so  that  the 
water  in  it  is  at  a  higher  level  than  that  in  the  aspirator.  Close  the  clip. 
Disconnect  the  flask  and  open  the  clip  for  a  moment,  to  establish  atmos- 
pheric pressure  in  the  flask.  Weigh.  The  calculation  is  identical  with  that 
given  for  O. 

What  is  the  ratio  between  the  weights  of  equal  vols.  of  N  and  H  ? 

(4)  Is  air  a  chemical  compound? 

How  would  you  determine  the  weight  of  a  litre  of  air  ? 

(5)  Make  an  analysis  of  air  by  Hempel's  apparatus. l 
(Study  Richter,  pp.  116-125.) 

NITROGEN  AND  HYDROGEN. 
AMMONIA, 

(6)  Preparation  :  Heat  an  intimate  mixture  of  finely  powdered  ammo- 
nium chloride  and  caustic  lime  in  a  flask  ;  conduct  the  evolved  gas  through 
a  tube  filled  with  small  pieces  of  lime,  and  collect  it  in  jars  or  test  tubes 
over  mercury. 


This  analysis  should  be  performed  by  the  demonstrator. 


What  is  the  object  of  the  lime  in  the  tube?  Why  can  you  not  dry  the 
gas  by  passing  it  through  H2SO4  or  CaCl2?  Why  should  it  be  collected 
over  mercury. 

y  i'o    27  (?)    ^s  ammonia   gas    combustible?      Does  it 

/~\  support  combustion?     /.  Conduct  NH3  through  a 

t?////'  S<9  28  glass  tube,  and  insert  this  into  a  wider  tube  filled 
with  oxygen  (Fig.  27}.  Apply  a  flame.  The  am- 
monia gas  will  ignite  and  continue  to  burn.  2. 
Heat  concentrated  ammonia  water  in  a  beaker 
until  there  is  an  abundant  disengagement  of  gas, 
then  conduct  a  rapid  current  of  oxygen  through 
the  liquid,  and  lower  a  glowing  spiral  of  platinum 
into  the  beaker  (as  in  Fig.  28}.  What  happens  ? 

Note  the  order  of   NH3    (caution  !).      Is    it 
lighter  than  air  ?     Soluble  in  water  ? 

(8)  Prepare  an  aqueous  solution  of  ammonia. 
What  are  its  properties  ? 

Add  red  litmus  to  some  of  the  solution  (?),  and  then  neutralize  carefully 
with  dilute  HC1.  Evaporate  to  dryness.  Compare  the  product  with  the 
ordinary  NH4C1.  Test  it  for  Cl  (?).  Heat  a  little  of  it  with  sodium  hydrate  (?). 
Heat  another  portion  on  a  platinum  foil  (?). 

(9)  Determine  the  weight  of  a  litre  of  NH$. 

Fill  a  dry  flask  with  the  gas  by  tipward  displacement,  and  proceed 
exactly  as  under  chlorine.  What  is  the  density  of  NHS  ? 

(10)  To  determine  the  quantitative  composition  of  NH,,  perform  experi- 
ments i  and  2  on  pp.  130  and  131,  in  Richter. 

Write  out  a  summary.     (Read  Richter,  pp.  125-131.) 

NITROGEN  AND  THE  HALOGENS. 

(u)  Pour  an  alcoholic  solution  of  iodine  into  strong  ammonia  water. 
Collect  the  precipitate  on  a  filter  and  wash  it  with  water.  Open  the  moist 
filter  ;  tear  it  into  small  pieces  and  spread  these  on  a  board.  After  thej 
have  become  dry,  touch  them  with  the  end  of  a  rod  (?).  Ask  for  instruc- 
tions !  (Read  Richter,  pp.  132-133.) 

NITROGEN  AND  OXYGEN. 

(12)  Hyponitrous  oxide  —  N2O.     /.  Place  aboutsgrms.  of  ammonium 
nitrate  in  a  small  retort ;  add  a  little  water,  and  apply  heat.     Collect  the 
product  over  warm  water.     2.  Test  it  with  a  glimmering  chip  ;  j.  with 
burning  phosphorus  ;  4.  with  burning  sulphur.     5.  Mix  equal  volumes  of 
this  gas  and  of  H,  and  apply  a  flame.     What  other  gas  does  it  resemble  in 
its  properties  ?     (Read  Richter,  pp.  212-213.) 

(13)  Nitric  oxide  —  NO.      /.  Pour  dilute   HNO;J    (sp.  gr.    1-2)    upon 
copper  turnings  contained  in  an  evolution  flask.     Cool,  and  allow  the  red 
fumes,  which  form  at  first,  to  escape  ;  then  collect  the  colorless  product 
over  water.     2.  What  occurs  when  this  gas  comes  in  contact  with  the  air  ? 
Is  it  the  O  or  the  N  of  the  air  that  acts  upon  the  gas  ?    j.  Apply  the  tests 
given  under   (12)  to  this  gas  (?).     How  can   NO  be   distinguished   from 
oxygen?    4.  Fill  a  cylinder  with  NO,  and  add  a   few  drops  of  CS2,  shake 


i8 


well  and  bring  a  flame  to  the  mouth  of  the  vessel  (?).  5.  Pass  a  current  of 
NO  into  a  strong  solution  of  ferrous  sulphate.  What  occurs?  After  the 
solution  has  become  saturated  with  the  gas  heat  it  to  boiling  (?).  6.  Pass 
the  gas  into  a  solution  of  potassium  permanganate  (?) . 

(14)  Nitrogen  trioxide— N2O3.     (Read  Richter,  pp.  205-206.) 
Nitrous  Acid— UNO  2 .     (Richter,  p.  206.) 

(15)  Nitrogen  tetr oxide,  N2O4,  and  dioxide,  NO2.     /.  Heat  10  grams 
of  dry  lead  nitrate  in  a  test  tube  ;  condense  the  escaping  vapors  in  a  well- 
cooled  receiver.     What  are  the  vapors,  and  what  is  the  condensed  liquid  > 
Note  the  color.     2.  What  is  the  action  of  cold  water,  and  of  aqueous  solu- 
tions of  the  alkalies  upon  N2O4  ?     What  do  these  reactions  indicate  in 
respect  to  the  composition  of  this  compound?     (Richter,    pp.    207-208.) 
j.  What  is  its  action  upon  potassium  iodide  ? 

(16)  Nitrogen  pentoxide,  N2O5.     (Richter,  p.  205.) 

NITRIC  ACID. — HNO3. 

/.  Preparation. — In  a  retort  heat  a  mixture  of  sodium  nitrate  and  sul- 
phuric acid  in  proportions  corresponding  to  the  equation  (?)  : 
NaN03  +  H2S04  =  NaHSO4  +  HNO3. 

Collect  the  product  in  a  cold  receiver. 

2.  What  are  the  physical  properties  of  HNO8  ?  Color  ?  Odor  ?  Action 
on  litmus  (diluted  with  H2O)  ?  j.  What  action  has  it  on  indigo  ?  Upon  the 
skin  ?  4.  Notice  the  effect  of  the  acid  upon  the  following  metals:  Cu,  Fe, 
Pb,  Zn,  Sn.  Write  the  reaction  for  each  one.  5.  Cover  powdered  sulphur 
with  the  acid,  and  warm  (?).  Dilute  with  water,  filter,  and  test  the  liquid 
with  Bad  2  (?)•  6.  Introduce  a  piece  of  ignited  charcoal  into  the  acid. 
What  takes  place  ?  7.  Add  a  few  drops  of  HNO3  to  a  solution  of  ferrous 
sulphate  (?)  ;  warm  the  solution  (?). 

(17)  Determine  the  quantity  of  HNOZ  in  a  solution,  by   Schultze's 
method. 

This  method  is  based  upon  the  following  reaction  : 

HN03  4-  3FeCl2  +  3HC1  =  NO  +  3FeCl3. 

We  determine  the  quantity  of  NO  which  is  formed,  and  calculate  from  it 
the  quantity  of  HNO3  necessary  to  produce  it. 

Arrange  the  apparatus  shown  in  Fig.  29. 

Put  the  solution  to  be  examined  into  the  flask  A,  and  concentrate  it,  by 
boiling,  to  about  50  cc.  While  boiling,  let  the  clips  c  and  d  be  open,  for 
the  escape  of  the  steam.  The  cistern 
B  and  the  graduated  tube  D  contain  a 
solution  of  NaOH  (10  per  cent.),  which 
has  been  boiled  shortly  before  com- 
mencing the  experiment.  After  boil- 
ing the  contents  of  A,  close  clip  c, 
and  let  the  steam  escape  at  d.  Finally 
close  this,  and  remove  the  lamp  from 
under  the  flask.  A  vacuum  is  now 
produced  within  the  flask,  and  the 
rubber  tubes  d  and  c  flatten  in  conse- 
quence. While  this  operation  has 
been  going  on,  a  solution  of  ferrous  chloride  should  have  been  prepared,  by 


19 

dissolving  iron  nails  in  strong  HC1.  This  solution  should  be  saturated. 
Introduce  25  cc.  of  it  into  A.  This  is  done  by  first  filling  the  glass  tube  e 
with  water  (by  means  of  the  wash  bottle),  then  dipping  it  into  the  iron  solu- 
tion contained  in  a  beaker  and  opening  the  clip  d.  The  solution  rapidly 
passes  into  A  ;  close  d  in  time  to  prevent  the  entrance  of  .air.  Now  care- 
fully boil  the  liquid  in  A,  and,  as  soon  as  the  rubber  tubes  at  £and  d  become 
distended,  open  c,  so  that  the  gases  can  pass  over  into  D.  CO2  and  steam 
will  be  absorbed  by  the  NaOH,  while  NO  collects  in  the  tube.  When  the 
volume  of  the  gas  no  longer  increases,  remove  the  graduated  tube  from  the 
delivery  tube  ;  close  it  with  the  thumb,  and  transfer  it  to  a  large  cylinder  of 
water,  where  the  volume  of  the  gas  is  read  off.  Note  the  temperature  of  the 
water  and  the  barometric  ^pressure. 
Calculation  : 

Observed  vol.  of  the  gas,        - v 

Vol.  of  gas  at  o°  C.  and  760  mm., v0 

Barometric  pressure, p 

Temperature  of  water, t 

Aqueous  tension, pr 

v  _          vX(p-px) 

(i  +  '00367  t)  X  760 

By  multiplying  v0  by  2-413  we  obtain  the  N2O5  in  milligrams.  Dividing 
this  product  by  the  number  of  100  cc.  of  water  originally  used,  will  give  the 
parts  of  N2O5  in.  100,000  parts  of  the  water. 

Problems. — (i)  Required  i  cu.  m.  of  N.  How  much  air  is  to  be  deprived 
of  O  ;  and  how  much  P  must  be  burned,  if  62  pts.  of  P  unite  with  80  pts.  of  O  t 

(2)  How  much  HNO3,  containing  46  per  cent,  of  water,  may  be  obtained 
from  1,700  grms.  of  NaNO3,  and  how  much  water  must  be  taken? 

(3)  How  many  grams  of  NH3  will  be  absorbed  by  5  litres  of  H2O,  if 
the  latter  absorbs  500  times  jts  volume  of  the  gas?    4.  Ten  litres  of  water 
having  absorbed  700  times  their  volume  of  ammonia,  what  are  the  least 
amounts  of  NH4C1  and  CaO  necessary  for  producing  this  solution  ? 

PHOSPHORUS. — P. 

(1)  /.  Determine  the  physical  properties  of  the  active  and   the  red 
varieties.     2.  I,et  a  small  piece  of  the  active  variety  inflame  in  the  air. 
Will   the  red  variety   do  this?    j.  Throw  a  small   piece   of   the    yellow 
variety  into  ajar  of  dry  Cl  (?).     Repeat  with  the  red  variety  (?).     4.  Bring 
a  small  dry  piece  of  active  P  in  contact  with  iodine  (?).    5.  Heat  a  flask 
containing  a  small  piece  of  P  and  water  until  the  former  is  melted,  then 
pass  a  current  of  oxygen  through  a  delivery  tube  into  the  melted  phos- 
phorus (?).     (Study  Richter,  pp.  133-136.) 

PHOSPHORUS  AND  HYDROGEN. 

(2)  PAosphme—PH3. — /.  Fill  a  flask  almost    full    with  a  moderately- 
concentrated  NaOH  solution.     Add  a  few  pieces  of  P,  and  heat  carefully. 
When  the  air  in  the  neck  of  the  flask  has  been  expelled  by  the  escaping 
gas,  insert  a  cork  with  a  delivery  tube,  the  other  end  of  which  dips  under 
warm  water.     What  becomes  of  the  gas  as  it  escapes  into  the  air  ? 

(Richter,  pp.  136-139.) 

Is  there  any  similarity  between  PH3  and  NH3  ? 

(3)  PHOSPHORUS  AND  THE  HALOGENS. 


20 

/.  Pass  a  current  of  dry  CO2  gas  into  a  retort,  the  bottom  of  which  is 
•covered  with  dry  sand.  When  all  the  air  has  been  expelled,  introduce  some 
well-dried  pieces  of  P,  and  replace  the  CO2  by  a  stream  of  dry  Cl.  Connect 
the  neck  of  the  retort  with  a  Liebig's  condenser,  and  collect  the  product  in 
a  receiver.  It  is  phosphorus  trichloride.  What  are  its  properties  ?  Pour 
•some  of  it  into  water  (?). 

2.  Place  a  little  PC13  in  a  dry  test  tube,  and  pass  a  stream  of  dry  Cl  upon 
its  surface.  What  is  the  result  ? 

PHOSPHORUS  AND  OXYGEN.     (Richter,  pp.  214-219). 

(4)  7.  Prepare phospho rus pentoxide,  P2O5,  by  burning  a  carefully  dried 
piece  of  P  under  a  dry  bell-jar.  2.  Drop  a  portion  of  the  product  into  water  (?). 

(5)  Orthophosphoric  acid,  H8PO4  ;    metaphosphoric  acid,  HPO3,    and 
Pyrophosphoric  a^id,  H4P2O7.     How  are  these  acids  obtained?     How  many 
series  of  salts  are  derived  from  them?     By  what  names  would  you  distin- 
guish the  different  salts  ? 

/.  Dissolve  some  Na2HPO4  in  water  and  test  the  solution  with  AgNO8, 
FeCl3,  and  (NH4)2  MoO4.  What  do  you  observe  in  each  case  ?  2.  Dissolve 
fused  Na2HPO4  in  water,  and  perform  the  same  tests  with  its  solution,  j. 
Heat  salt  of  phosphorus  (NaNH4HPO4)  until  it  no  longer  effervesces,  and 
dissolve  the  residue  in  water.  How  does  this  solution  behave  upon  treating 
with  the  above  reagents  ?  4.  Acidify  a  portion  of  the  last-named  solution 
with  acetic  acid,  and  add  a  solution  of  albumen  to  it.  Result  ? 

(6)  Phosphorus  trioxide—T?2Q3y  and  phosphorous  acid — H3P    3. 
Pour  PCI  3  into  water.     Evaporate  the  solution  to  syrupy  consistency  (?). 
(Study  Richter,  p.  216). 

( 7 )  Hypophosphorous  acid — H  3  PO  2 . 

Heat  pieces  of  phosphorus  in  a  porcelain  dish  with  a  moderately  strong 
baryta  solution.  When  no  more  PH3  is  formed,  cool,  filter,  and  pass  CO2 
into  the  solution  until  it  shows  a  neutral  reaction  to  litmus.  Toward  th« 
-end,  the  solution  should  be  warmed.  Filter  and  evaporate  to  suitable  con- 
centration. Hypophosphite  of  barium  will  crystallize. 

How  may  the  free  acid  be  obtained  from  this  salt  ? 


ARSENIC.—  As. 

(i)  Study    the    physical   and    chemical    properties    of   this    element. 
{Richter,  pp.  142  and  143.)     Are  they  analogous  to  those  of  phosphorus? 

(1)  /.  In  a  tube  of  hard  glass  heat  a  small  piece  of  As  to  redness. 
Result?    2.  Heat  As  with  the  oxidizing  flame  upon  charcoal  (?).    j.  Dis- 
solve powdered  As  in  strong  HNO3  (?). 

ARSENIC  AND  HYDROGEN. 

(2)  Perform  Marsh's  test  for  As.1 

Arrange   the   apparatus  shown    in 
Fig-  30.     To   the   mixture   of  Zn   and 
dilute   H2SO4  contained    in   a,   add   a 
small  portion  of  the  solution  to  be  tested 
for  As.     The  liberated  gas  contains  H 
and     AsH3  '  (arsine).        It    is     passed 
through  c,   filled   with   CaCl2    (?),  and 
then  through  d,  a  tube  of  hard  glass,  contracted  at  several  places.     After 
1  Ask  for  instructions  ! 


21 

all  the  air  has  been  expelled  from  the  apparatus,  ignite  the  hydrogen.  If 
As  is  present  it  will  burn  with  a  bluish  white  flame,  and  white  vapors  will 
be  given  off.  Hold  a  cold  porcelain  plate  in  the  flame  (?).  Heat  the  tube 
d,  as  shown  in  the  figure  (?). 

Great  care  must  be  exercised  in  performing  this  test,  as  the  arsine 
gas  is  extremely  poisonous  ! 

ANTIMONY. — Sb. 

(i)  Study  this  element  in  the  same  manner  as  As.  Distinguish  between. 
SbH3  and  AsH3. 

/.  Treat  the  metallic  mirror  obtained  in  Marsh's  apparatus,  with  a 
freshly  prepared  solution  of  hypochlorite  of  sodium  :  As  dissolves  readily, 
while  Sb  is  scarcely  acted  upon.  2.  Heat  a  piece  of  the  tube,  in  which  a 
mirror  has  formed,  in  the  flame  of  the  Bunsen  burner.  Dissolve  the  pro- 
duct in  dilute,  warm  HC1,  and  add  H2S  water  (?).  j.  Treat  the  spot  formed 
upon  a  cold  porcelain  plate  with  yellow  ammonium  sulphide,  and  evaporate 
the  solution  at  a  gentle  heat  (?). 

Problems. — (i)  How  much  P  can  be  obtained  from  250  grins,  of  bones  ? 
(2)  10  grms.  of  P  give  what  vol.  of  phosphine?  (3)  What  is  the  weight 
of  the  product  remaining,  after  evaporating  a  solution  of  10  grms.  of  As  in 
HNO,? 


CHAPTER    VI. 

CARBON   GROUP — CARBON   AND  SILICON. 

CARBON. — C. 

(1)  How  many  allotropic  modifications  of  this  element  are  known? 
What  are  their  principal  properties  ?     /.  Collect  some  NH3  gas  in  a  gradu- 
ated tube  over  mercury  ;  introduce  a  piece  of  freshly-ignited  charcoal,  and 
observe  the  diminution  in  the  volume  of  the  gas.     2.  Boil  a  dilute  litmus 
solution  with  powdered  animal  charcoal  ;  filter.      Result?     j.  Substitute 
indigo  for  the  litmus  in  the  preceding  experiment  (?).     4..  Determine  the 
coke,  volatile  matter  and  ash  in  a  sample  of  anthracite  coal. 

(Read  Richter,  pp.  150-152.) 
* 

CARBON  AND  HYDROGEN. 

(2)  Methane  (Marsh  gas)— CH4. 

/.  Preparation. — Heat  a  dried  mixture  of  sodium  acetate  and  sodium 
hydrate  in  an  iron  tube.  Collect  the  gas  over  water.  Note  its  color,  odor 
and  taste.  Does  it  burn  ?  2.  Mix  i  vol.  of  it  with  7  to  8  times  its  vol.  of 
air  and  explode  by  applying  a  flame.  (Ask  for  instructions  !) 

How  would  you  determine  the  molecular  weight  of  this  compound  ? 

(3)  Make  a  eudiometric  combustion  of  i  vol.  of  CH4  with  2  vols.  of  O 
as  described  in  Richter,  p.  121. 

(4)  Ethane— CaH6.     (Richter,  p.  153.) 

Ethylene — C2H4.  Into  a  ^  litre  flask  put  5  grms.  of  alcohol  and  30 
grms.  of  H2SO4.  Heat  to  160°  C.  and  add  gradually  a  mixture  of  i  part  of 
alcohol  and  2  parts  of  H2SO4.  Note  the  color,  odor,  taste  and  solubility  of 
the  escaping  gas.  What  is  its  most  characteristic  property  ? 

(5)  Acetylene — C2H2.     Light  a  Bunsen  burner  at  the  base  and  turn  it 


22 

•down,  so  that  the  flame  is  small.     Acetylene  can  be  recognized,  among  the 
products  of  combustion,  by  its  characteristic  odor. 

(6)  CARBON  AND  THE  HALOGENS.  (Richter,  p.  160.) 

CARBON  AND  OXYGEN. 

(7)  Carbon  dioxide— CO 2. 

i.  Preparation, — Upon  pieces  of  marble,  contained  in  an  evolution 
flask,  pour  dilute  HC1.  Conduct  the  resulting  gas  through  water  and 
through  cone.  H2SO4.  It  may  be  collected  either  by  downward  displace- 
ment of  the  air,  or  over  mercury.  2.  Note  color,  taste  and  odor  of  this  gas. 
Is  it  soluble  in  water  ?  How  does  its  weight  compare  with  that  of  air  ? 
Does  it  burn  or  support  combustion  ?  j.  Conduct  a  current  of  CO2  into  a 
solution  of  NaOH,  evaporate  the  liquid,  and  test  the  residue  for  Na2CO3  (?). 
4.  To  different  portions  of  Na2CO3  solution,  add  solutions  of  MgSO4,  BaCl2, 
Pb(N03)2,  ZnS04  (?). 

(Study  Richter,  pp.  228-232.) 

(8)  Carbon  monoxide— CO. 

Preparation. — /.  In  a  tube  of  hard  glass  heat  zinc  dust  to  faint  redness, 
while  conducting  a  slow  current  of  CO2  over  it.  In  what  respect  does  the 
product  differ  from  CO2.  2.  Pass  steam  over  red-hot  pieces  of  C.  Result  ? 
j.  Heat  crystals  of  oxalic  acid  with  cone.  H2SO4  in  a  flask,  and  wash  the 
product  with  NaOH  solution.  Write  the  reaction.  Study  the  properties  of 
this  gas.  (Richter,  p.  233). 

(9)  Carbon  disulphide—£S2. 

Perform  some  of  the  experiments  indicated  in  Richter,  p.  234. 

(10)  CARBON  AND  NITROGEN. 

/.  In  a  dry  test  tube  heat  a  nitrogenous  carbon  compound  with  a  small 
piece  of  K.  Cool  and  add  water.  KCN  is  formed  and  can  be  tested  with 
AgNO8.  2.  Convert  a  portion  of  the  KCN  into  KCNS  by  evaporating  with 
(NH4)2S.  Test  with  FeCl8.  j.  To  a  solution  of  FeSO4  add  potassium 
ferrocyanide.  What  results?  4.  What  is  the  action  of  the  ferrocyanide 
upon  solutions  of  ferric  salts  ? 

(n)  Study  the  nature  of  flame.  Make  the  experiments  described  in 
Richter,  pp.  155-160. 


SIUCON.—  Si. 

(i)  Preparation. — Make  an  intimate  mixture  of  i  grm.  magnesium 
powder  and  4  grms.  of  finely  powdered  quartz-sand.  Heat  this  in  a  wide 
lube  of  hard  glass,  to  bright  redness.  It  is  best  to  use  the  blast  lamp  for 
this  purpose.  That  part  of  the  tube,  containing  the  mixture,  should  be 
rotated  in  the  flame.  The  residue,  after  a  few  minutes'  heating,  is  allowed 
to  cool,  and  treated  with  water  containing  HC1.  The  product  consists  of 
.amorphous  silicon  and  undecomposed  quartz.  2.  Test  the  action  of  the 
following  reagents  upon  Si  :  sulphuric,  nitric  and  hydrofluoric  acids,  potash 
solution  and  a  current  of  HC1  gas.  3.  Fuse  a  portion  of  the  amorphous 
silicon  with  granulated  zinc  in  a  closed  Hessian  crucible.  Heat  the  mass 
for  some  time  to  the  boiling  point  of  Zn.  Extract  the  residue  with  dilute 
HC1  ;  what  remains?  (Read  Richter,  p.  161.) 


23 

SIWCON  AND  OXYGEN. 

(2)  Silicon  dioxide  (Silica,  Quartz)— SiO2. 

7.  Test  its  solubility  in  the  various  acids  and  alkalies.  2.  Fuse  a  mix- 
ture of  i  grm.  of  finely  powdered  quartz  with  4  grms.  of  Na2CO3,  in  a 
platinum  crucible.  Dissolve  the  product  in  water,  j.  To  a  portion  of  this 
solution  add  HC1,  and  evaporate  to  complete  dryness.  Take  up  the  residue 
with  water  and  filter  off  the  insoluble  portion.  4.  To  another  portion  of 
the  aqueous  solution  of  the  fusion  add  NH4C1.  (?)  5.  Make  a  bead  of  salt  of 
phosphorus  ;  bring  a  fragment  of  a  silicate  or  of  quartz  into  it,  and  heat  in 
the  blow-pipe  flame  for  a  few  moments  (?) . 

BORON. — B. 

(1)  Preparation  similar  to  that  of  Si.     What  are  its  properties  ?     Does 
it  unite  directly  with  other  elements  ?     Is  it  known  in  several  allotropic 
modifications  ?     What  is  the  valency  of  this  element  ? 

(Read  Richter,  p.  240  and  241.) 

BORON  AND  OXYGEN. 

(2)  Boric  acid — BO3. 

7.  Dissolve  borax  iii  4  parts  of  boiling  water,  add  HC1  to  acid  reaction, 
and  allow  to  cool.  What  crystallizes  out  of  the  solution  ?  Dry  some  of  the 
product  by  pressing  it  between  filter  paper.  Test  its  solubility  in  water  and 
in  alcohol.  What  do  you  observe  on  igniting  the  alcoholic  solution  ? 
Moisten  a  piece  of  turmeric  paper  with  an  aqueous  solution  of  boric  acid, 
and  dry  at  a  gentle  heat.  What  happens? 

Problems. — (i)  How  much  CO2  results  from  the  combustion  of  12  grms. 
of  carbon?  (2)  How  much  CO2  will  an  indefinite  quantity  of  CaCO3  give, 
when  acted  upon  by  4*666  grms.  of  muriatic  acid,  containing  30  per  cent,  of 
pure  HC1  ?  (3)  How  many  cubic  decimeters  of  CO  can  be  obtained  from 
90  grms.  of  oxalic  acid  ?  (4)  What  amount  of  SiO2  can  be  obtained  from  2 
grms.  of  Wollastonite  (CaSiO3)  ?  (5)  What  is  the  theoretical  quantity  of 
boric  acid  obtainable  from  15  grms.  of  borax  (Na2B4O7  -f-  ioH2O)  ? 


14  DAY  USE 

RETURN  TO  DESK  FROM  WHICH  BORROWED 

LOAN  DEPT. 

This  book  is  due  on  the  last  date  stamped  below,  or 

on  the  date  to  which  renewed. 
Renewed  books  are  subject  to  immediate  recall. 


QMay'BORT 

IC'D  LD 

MAY  C      I960 

LD  21A-50m-4,'60 
(A9562slO)476B 


General  Library 

UniTersity  of  California 

Berkeley 


